diff options
Diffstat (limited to 'drivers/counter/ti-eqep.c')
| -rw-r--r-- | drivers/counter/ti-eqep.c | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c new file mode 100644 index 000000000000..1ff07faef27f --- /dev/null +++ b/drivers/counter/ti-eqep.c @@ -0,0 +1,466 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2019 David Lechner <david@lechnology.com> + * + * Counter driver for Texas Instruments Enhanced Quadrature Encoder Pulse (eQEP) + */ + +#include <linux/bitops.h> +#include <linux/counter.h> +#include <linux/kernel.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/regmap.h> + +/* 32-bit registers */ +#define QPOSCNT 0x0 +#define QPOSINIT 0x4 +#define QPOSMAX 0x8 +#define QPOSCMP 0xc +#define QPOSILAT 0x10 +#define QPOSSLAT 0x14 +#define QPOSLAT 0x18 +#define QUTMR 0x1c +#define QUPRD 0x20 + +/* 16-bit registers */ +#define QWDTMR 0x0 /* 0x24 */ +#define QWDPRD 0x2 /* 0x26 */ +#define QDECCTL 0x4 /* 0x28 */ +#define QEPCTL 0x6 /* 0x2a */ +#define QCAPCTL 0x8 /* 0x2c */ +#define QPOSCTL 0xa /* 0x2e */ +#define QEINT 0xc /* 0x30 */ +#define QFLG 0xe /* 0x32 */ +#define QCLR 0x10 /* 0x34 */ +#define QFRC 0x12 /* 0x36 */ +#define QEPSTS 0x14 /* 0x38 */ +#define QCTMR 0x16 /* 0x3a */ +#define QCPRD 0x18 /* 0x3c */ +#define QCTMRLAT 0x1a /* 0x3e */ +#define QCPRDLAT 0x1c /* 0x40 */ + +#define QDECCTL_QSRC_SHIFT 14 +#define QDECCTL_QSRC GENMASK(15, 14) +#define QDECCTL_SOEN BIT(13) +#define QDECCTL_SPSEL BIT(12) +#define QDECCTL_XCR BIT(11) +#define QDECCTL_SWAP BIT(10) +#define QDECCTL_IGATE BIT(9) +#define QDECCTL_QAP BIT(8) +#define QDECCTL_QBP BIT(7) +#define QDECCTL_QIP BIT(6) +#define QDECCTL_QSP BIT(5) + +#define QEPCTL_FREE_SOFT GENMASK(15, 14) +#define QEPCTL_PCRM GENMASK(13, 12) +#define QEPCTL_SEI GENMASK(11, 10) +#define QEPCTL_IEI GENMASK(9, 8) +#define QEPCTL_SWI BIT(7) +#define QEPCTL_SEL BIT(6) +#define QEPCTL_IEL GENMASK(5, 4) +#define QEPCTL_PHEN BIT(3) +#define QEPCTL_QCLM BIT(2) +#define QEPCTL_UTE BIT(1) +#define QEPCTL_WDE BIT(0) + +/* EQEP Inputs */ +enum { + TI_EQEP_SIGNAL_QEPA, /* QEPA/XCLK */ + TI_EQEP_SIGNAL_QEPB, /* QEPB/XDIR */ +}; + +/* Position Counter Input Modes */ +enum { + TI_EQEP_COUNT_FUNC_QUAD_COUNT, + TI_EQEP_COUNT_FUNC_DIR_COUNT, + TI_EQEP_COUNT_FUNC_UP_COUNT, + TI_EQEP_COUNT_FUNC_DOWN_COUNT, +}; + +enum { + TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES, + TI_EQEP_SYNAPSE_ACTION_RISING_EDGE, + TI_EQEP_SYNAPSE_ACTION_NONE, +}; + +struct ti_eqep_cnt { + struct counter_device counter; + struct regmap *regmap32; + struct regmap *regmap16; +}; + +static int ti_eqep_count_read(struct counter_device *counter, + struct counter_count *count, unsigned long *val) +{ + struct ti_eqep_cnt *priv = counter->priv; + u32 cnt; + + regmap_read(priv->regmap32, QPOSCNT, &cnt); + *val = cnt; + + return 0; +} + +static int ti_eqep_count_write(struct counter_device *counter, + struct counter_count *count, unsigned long val) +{ + struct ti_eqep_cnt *priv = counter->priv; + u32 max; + + regmap_read(priv->regmap32, QPOSMAX, &max); + if (val > max) + return -EINVAL; + + return regmap_write(priv->regmap32, QPOSCNT, val); +} + +static int ti_eqep_function_get(struct counter_device *counter, + struct counter_count *count, size_t *function) +{ + struct ti_eqep_cnt *priv = counter->priv; + u32 qdecctl; + + regmap_read(priv->regmap16, QDECCTL, &qdecctl); + *function = (qdecctl & QDECCTL_QSRC) >> QDECCTL_QSRC_SHIFT; + + return 0; +} + +static int ti_eqep_function_set(struct counter_device *counter, + struct counter_count *count, size_t function) +{ + struct ti_eqep_cnt *priv = counter->priv; + + return regmap_write_bits(priv->regmap16, QDECCTL, QDECCTL_QSRC, + function << QDECCTL_QSRC_SHIFT); +} + +static int ti_eqep_action_get(struct counter_device *counter, + struct counter_count *count, + struct counter_synapse *synapse, size_t *action) +{ + struct ti_eqep_cnt *priv = counter->priv; + size_t function; + u32 qdecctl; + int err; + + err = ti_eqep_function_get(counter, count, &function); + if (err) + return err; + + switch (function) { + case TI_EQEP_COUNT_FUNC_QUAD_COUNT: + /* In quadrature mode, the rising and falling edge of both + * QEPA and QEPB trigger QCLK. + */ + *action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES; + break; + case TI_EQEP_COUNT_FUNC_DIR_COUNT: + /* In direction-count mode only rising edge of QEPA is counted + * and QEPB gives direction. + */ + switch (synapse->signal->id) { + case TI_EQEP_SIGNAL_QEPA: + *action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE; + break; + default: + *action = TI_EQEP_SYNAPSE_ACTION_NONE; + break; + } + break; + case TI_EQEP_COUNT_FUNC_UP_COUNT: + case TI_EQEP_COUNT_FUNC_DOWN_COUNT: + /* In up/down-count modes only QEPA is counted and QEPB is not + * used. + */ + switch (synapse->signal->id) { + case TI_EQEP_SIGNAL_QEPA: + err = regmap_read(priv->regmap16, QDECCTL, &qdecctl); + if (err) + return err; + + if (qdecctl & QDECCTL_XCR) + *action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES; + else + *action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE; + break; + default: + *action = TI_EQEP_SYNAPSE_ACTION_NONE; + break; + } + break; + } + + return 0; +} + +static const struct counter_ops ti_eqep_counter_ops = { + .count_read = ti_eqep_count_read, + .count_write = ti_eqep_count_write, + .function_get = ti_eqep_function_get, + .function_set = ti_eqep_function_set, + .action_get = ti_eqep_action_get, +}; + +static ssize_t ti_eqep_position_ceiling_read(struct counter_device *counter, + struct counter_count *count, + void *ext_priv, char *buf) +{ + struct ti_eqep_cnt *priv = counter->priv; + u32 qposmax; + + regmap_read(priv->regmap32, QPOSMAX, &qposmax); + + return sprintf(buf, "%u\n", qposmax); +} + +static ssize_t ti_eqep_position_ceiling_write(struct counter_device *counter, + struct counter_count *count, + void *ext_priv, const char *buf, + size_t len) +{ + struct ti_eqep_cnt *priv = counter->priv; + int err; + u32 res; + + err = kstrtouint(buf, 0, &res); + if (err < 0) + return err; + + regmap_write(priv->regmap32, QPOSMAX, res); + + return len; +} + +static ssize_t ti_eqep_position_floor_read(struct counter_device *counter, + struct counter_count *count, + void *ext_priv, char *buf) +{ + struct ti_eqep_cnt *priv = counter->priv; + u32 qposinit; + + regmap_read(priv->regmap32, QPOSINIT, &qposinit); + + return sprintf(buf, "%u\n", qposinit); +} + +static ssize_t ti_eqep_position_floor_write(struct counter_device *counter, + struct counter_count *count, + void *ext_priv, const char *buf, + size_t len) +{ + struct ti_eqep_cnt *priv = counter->priv; + int err; + u32 res; + + err = kstrtouint(buf, 0, &res); + if (err < 0) + return err; + + regmap_write(priv->regmap32, QPOSINIT, res); + + return len; +} + +static ssize_t ti_eqep_position_enable_read(struct counter_device *counter, + struct counter_count *count, + void *ext_priv, char *buf) +{ + struct ti_eqep_cnt *priv = counter->priv; + u32 qepctl; + + regmap_read(priv->regmap16, QEPCTL, &qepctl); + + return sprintf(buf, "%u\n", !!(qepctl & QEPCTL_PHEN)); +} + +static ssize_t ti_eqep_position_enable_write(struct counter_device *counter, + struct counter_count *count, + void *ext_priv, const char *buf, + size_t len) +{ + struct ti_eqep_cnt *priv = counter->priv; + int err; + bool res; + + err = kstrtobool(buf, &res); + if (err < 0) + return err; + + regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, res ? -1 : 0); + + return len; +} + +static struct counter_count_ext ti_eqep_position_ext[] = { + { + .name = "ceiling", + .read = ti_eqep_position_ceiling_read, + .write = ti_eqep_position_ceiling_write, + }, + { + .name = "floor", + .read = ti_eqep_position_floor_read, + .write = ti_eqep_position_floor_write, + }, + { + .name = "enable", + .read = ti_eqep_position_enable_read, + .write = ti_eqep_position_enable_write, + }, +}; + +static struct counter_signal ti_eqep_signals[] = { + [TI_EQEP_SIGNAL_QEPA] = { + .id = TI_EQEP_SIGNAL_QEPA, + .name = "QEPA" + }, + [TI_EQEP_SIGNAL_QEPB] = { + .id = TI_EQEP_SIGNAL_QEPB, + .name = "QEPB" + }, +}; + +static const enum counter_count_function ti_eqep_position_functions[] = { + [TI_EQEP_COUNT_FUNC_QUAD_COUNT] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4, + [TI_EQEP_COUNT_FUNC_DIR_COUNT] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION, + [TI_EQEP_COUNT_FUNC_UP_COUNT] = COUNTER_COUNT_FUNCTION_INCREASE, + [TI_EQEP_COUNT_FUNC_DOWN_COUNT] = COUNTER_COUNT_FUNCTION_DECREASE, +}; + +static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = { + [TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES, + [TI_EQEP_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE, + [TI_EQEP_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE, +}; + +static struct counter_synapse ti_eqep_position_synapses[] = { + { + .actions_list = ti_eqep_position_synapse_actions, + .num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions), + .signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPA], + }, + { + .actions_list = ti_eqep_position_synapse_actions, + .num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions), + .signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPB], + }, +}; + +static struct counter_count ti_eqep_counts[] = { + { + .id = 0, + .name = "QPOSCNT", + .functions_list = ti_eqep_position_functions, + .num_functions = ARRAY_SIZE(ti_eqep_position_functions), + .synapses = ti_eqep_position_synapses, + .num_synapses = ARRAY_SIZE(ti_eqep_position_synapses), + .ext = ti_eqep_position_ext, + .num_ext = ARRAY_SIZE(ti_eqep_position_ext), + }, +}; + +static const struct regmap_config ti_eqep_regmap32_config = { + .name = "32-bit", + .reg_bits = 32, + .val_bits = 32, + .reg_stride = 4, + .max_register = 0x24, +}; + +static const struct regmap_config ti_eqep_regmap16_config = { + .name = "16-bit", + .reg_bits = 16, + .val_bits = 16, + .reg_stride = 2, + .max_register = 0x1e, +}; + +static int ti_eqep_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct ti_eqep_cnt *priv; + void __iomem *base; + int err; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(base)) + return PTR_ERR(base); + + priv->regmap32 = devm_regmap_init_mmio(dev, base, + &ti_eqep_regmap32_config); + if (IS_ERR(priv->regmap32)) + return PTR_ERR(priv->regmap32); + + priv->regmap16 = devm_regmap_init_mmio(dev, base + 0x24, + &ti_eqep_regmap16_config); + if (IS_ERR(priv->regmap16)) + return PTR_ERR(priv->regmap16); + + priv->counter.name = dev_name(dev); + priv->counter.parent = dev; + priv->counter.ops = &ti_eqep_counter_ops; + priv->counter.counts = ti_eqep_counts; + priv->counter.num_counts = ARRAY_SIZE(ti_eqep_counts); + priv->counter.signals = ti_eqep_signals; + priv->counter.num_signals = ARRAY_SIZE(ti_eqep_signals); + priv->counter.priv = priv; + + platform_set_drvdata(pdev, priv); + + /* + * Need to make sure power is turned on. On AM33xx, this comes from the + * parent PWMSS bus driver. On AM17xx, this comes from the PSC power + * domain. + */ + pm_runtime_enable(dev); + pm_runtime_get_sync(dev); + + err = counter_register(&priv->counter); + if (err < 0) { + pm_runtime_put_sync(dev); + pm_runtime_disable(dev); + return err; + } + + return 0; +} + +static int ti_eqep_remove(struct platform_device *pdev) +{ + struct ti_eqep_cnt *priv = platform_get_drvdata(pdev); + struct device *dev = &pdev->dev; + + counter_unregister(&priv->counter); + pm_runtime_put_sync(dev), + pm_runtime_disable(dev); + + return 0; +} + +static const struct of_device_id ti_eqep_of_match[] = { + { .compatible = "ti,am3352-eqep", }, + { }, +}; +MODULE_DEVICE_TABLE(of, ti_eqep_of_match); + +static struct platform_driver ti_eqep_driver = { + .probe = ti_eqep_probe, + .remove = ti_eqep_remove, + .driver = { + .name = "ti-eqep-cnt", + .of_match_table = ti_eqep_of_match, + }, +}; +module_platform_driver(ti_eqep_driver); + +MODULE_AUTHOR("David Lechner <david@lechnology.com>"); +MODULE_DESCRIPTION("TI eQEP counter driver"); +MODULE_LICENSE("GPL v2"); |